Originally Posted by
Roelof
The engine is based on the Novarossi RX21 models.
Maybe the latest RX21 models then I think.
I still have in my "old engine corner" both a crank case for the RX21 (Novarossi Speed I think it was) and the SX21 EVO5, and I can asure you they are not the same....
Porting in both crank cases are totally different...
The SX21 EVO5 is exactly the same as the MAX MF 21...